Mechanical eraser



Patented Feb. 13, 1951 UNITED STATES ATENT OFFICE l Claims.

My invention relates to erasers for use generally in deleting marks,lines, letters and similar characters from typewritten and other sheetsand from drawings. Specically, the invention pertains to a mechanicaleraser of a type wherein a long slender strip of eraser material isenclosed in a long barrel from which it may be intermittently fed asnecessary to present additional eraser material as previously extendedmaterial is worn oli" in use.

Among the more important objects oi the invention are the following:

To provide an eraser of such size and shape that it may be held in themanner of a pencil and used with substantially the same accuracy as apencil;

To provide an eraser in which the erasing material is presented to thework in a relatively thin ribbon-like form so that it may be used toerase small areas such as individual characters in typewritten lines orindividual lines adjacent other lines in drawings;

To provide an eraser which is particularly adapted to erasing singlecharacters of typewritten material withouts removing the work` from thetypewriter and, if desired, without rotating the platen to move the workup into a more accessible position;

To provide an eraser in which practically all the erasing material maybe eiciently used for the purpose of erasing without the necessity ofcutting away and discarding or rubbing off portions of the material tokeep the working edge sharp;

To provide an eraser from which the eraser material may be convenientlyand rapidly extended as desired by a simple reciprocating action of aslider;

To provide an eraser in which the strip of eraser material is held rmlynear the point of use so that elastic deflection is minimized;

To provide an eraser into which refills may be readily inserted with aminimum of difliculty and delay and to provide an eraser in whichvarious grades of erasing material may be interchangeably used;

To provide an eraser in which the eraser material, except for the smallexposed portion currently available for use, is completely enclosed andprotected from accumulation of dirt, grease, perspiration, and otherobjectionable deposits; and

To provide an eraser incorporating a brush disposed on the end oppositethe erasing end in (Cl. 12B- 36) a form most convenient for cleaningerased materiai from the work.

Further objects of the invention will become apparent from the followingspecification and the drawing, which is intended for illustrationpurposes only, and in which:

Fig. 1 is a plan view of my improved mechanical eraser; y

Fig. 2 is a side view of the same;

Fig. 3 is an enlarged fragmentary longitudinal sectional view of theforward end of the eraser, taken on line 3 3 of Fig. l, but showing theeraser material as partially worn away;

Fig. 4 is a view similar to Fig. 3 showing the feeding slide as movedforwardly to project a new portion of the eraser material from the endof the device;

Fig. 5 is a similar view showing the eraser material as havingbeen fedforwardly and the feeding slide returned to inoperative position;

fig. 6 is an enlarged cross-sectional View, taken on line E-$ of Fig. 5;and

Fig. 7 is an enlarged cross-sectional View, taken on line l-l of Fig. 5.

Referring to the drawing in detail, the improved eraser consists of fourparts, namely, a barrel or holder I 0, a slider or feeding element l l,a strip of eraser material l2 and a brush assembly i3.

The holder I6 consists of a tube of substan- `tially rectangular crosssection having its corners rounded as shown in Fig. 6. The holder il)may be made from sheet metal struck up in a suitable die and folded tothe required shape, after which the lateral edges of the stock may besecured in overlapping engagement as shown in Fig. 6. At its forward ormuzzle end, the narrow sides of the holder Ill are slit as shown at l5so as to provide upper and lower resilient tines or jaws i6 and Il.Rearwardly of the jaws i6 and il, the wider top and bottom portions ofthe holder it are stamped with U-shaped cutouts il", thus providingresilient tongues or retaining pawls i8 and i9 which curve inwardly asshown in Fig. 3. Preferably the holder member I@ is provided with aseries of ribs 2li which serve as ringer grips to prevent slipping ofthe holder between the iingers during an erasing operation or duringfeeding of the eraser material in the manner to be later explained.

The brush assembly i3, referred to above, ccmprises a sheet metal cup 22in which the inner ends of a group of bristles 23 are clamped. The brushis applied to the rear end of the holder lll by merely inserting the cupthereinto. As before indicated, the brush is used for the purpose ofcleaning erased material from the work, and it will be apparent that italso serves to cover the rear end of the holder so as to exclude dustand other foreign matter from the interior of the holder.

The slider or feeding element II consists of a rectangular tube havingrounded corners and of a size adapting it to slide on the holder I atthe forward end thereof. The slider may be made by blanking, embossing,and forming a sheet of thin metal into rectangular cross section, thelateral edges of the sheet being resistance-welded along the lappedseam. At the forward or muzzle end of the slider, the material isdoubled or hemmed inwardly to form inwardly projecting lips 25, thusreducing the size of the opening at the forward end of the slider andreinforcing the thin flat-walled tube to provide greater stiffness. Atthe mid portion of the slider, its upper and lower sides have U-shapedcut-outs, thus providing resilient feeding pawls 26 and 21 which curveinwardly. Rearwardly of the pawls 26 and 21, the upper and lower sidesof the slider are embossed to provide transverse ribs 28 which serve asfinger-grips when the slider is moved longitudinally.

After the holder I and slider II have been fabricated, they areassembled by sliding the slider onto the muzzle end of the holder.During this movement, the pawls 26 and 21 are deiiected outwardly by thejaws I6 and I1 and the upper and lower sides of the holder Ii) untilthey pass the edges of the cut-out portions I1 in the upper and lowersides of the holder, at which time they spring inwardly into the cut-outportions I'i. The slider II may be pushed further onto the barrel I3until it is finally restrained by Contact of the inwardly projectinglips against the forward ends of the jaws i6 and I1. The slider II isshown in substantially this position in Fig. 5, and it will be notedthat engagement between the relatively rigid lips 25 and the readilydeiiectable jaws I6 and I1 forces the latter toward i each other. Afterthe slider l i has been thus assembled on the barrel or holder I, thepawls 26 and 21 act to prevent removal of the slider due to the factthat their forward ends move under the forward edges of the cut-outs I1.

The eraser strip I2 is preferably made in parallelepipedal form withrounded or chamfered corners to give clearance inside the barrel Il).Rubber-base eraser stocks are commonly available in different types andgrades for different kinds of work. For example, when erasing typedcharacters from hard bond papers, a hard and highly abrasive material isdesirable; for erasing typed or carbon paper characters from soft bondor sulphite papers, a medium hard eraser stock with moderate abrasivequalities may be used; and for erasing pencil lines, a medium soft stockhaving mild abrasive qualities is suitable.

With the various parts of the complete device now described and with theslider II assembled on the barrel Iii, the loading and feedingoperations are performed as follows:

To insert an eraser strip I2, the brush assembly I 3 is first removedfrom the rear end of the barrel IEJ, and the slider Il is movedforwardly on the barrel la to the limiting position determined bycontact of the pawls Z6 and 21 with the edges of the cut-outs I1. Alength of eraser stock I2 is inserted into the rearward end or breech ofthe barrel I6 in which it slides freely until its forward end engagesthe inner surfaces of the tongues I8 and I9. Additional pressure exertedagainst the rearward end of the strip i2 forces it between the tonguesI8 and I@ so that the forward end of the strip deiiects and passesbetween these tongues until it comes into contact with the innersurfaces of the pawls 26 and 2i'. Due to the relatively poor columnarqualities of the eraser strip I2 under compression loads, and due to thetendency of the material to deflect into frictional contact with theinner walls of the barrel IG, it is usually impossible to extend thefront end of the strip beyond the pawls 26 and 21 by applying furtherforce against the rearward end of the strip.

At this time the barrel is held in one hand with the thumb andforeiinger exercising a firm grip upon the ribs 20, and the slider II isgrasped between the thumb and forefinger of the other hand and pulledrearwardly along the barrel until light resistance to further movementis caused by contact of the inwardly turned lips 25 against the jaws I6and i1. During this rearward movement of the slider il, the forward tipsof the tongues I8 and i9, embedded in the eraser` strip i2, restrain thelatter from rearward motion which might be caused by contact of the tipsof the pawls 26 and 21 against the strip I2.

With the slider II in retracted position, it is then firmly grippedbetween the thumb and foreiinger of the operator so that the pressureapplied to the outer surfaces of the pawls 26 and 21 forces the lattertoward one another, and the tips of these pawls embed themselves in theflat upper and lower faces of the strip I2. With the pawls 26 and 21thus rmly gripping the strip i2, pressure is maintained and the sliderII is moved forwardly to the position shown in Fig. 4 where furthermovement is limited by contact between the pawls 26 and 21 and the edgeof the vcut-out I1. This forward movement of the slider II will carrythe eraser .strip forward a distance approximately equal to thattraveled by the slider itself. Pressure on the pawls 26 and 21 is thendiminished so that the tips of these pawls are no longer embedded in thestrip I2 and the slider is pulled back again to the position shown inFig. 3. Pressure is then re-applied to the pawls 26 and 21 whichre-embed themselves in the strip and the slider is again moved forwardlyto the limit of travel. Three or four such successive reciprocatorycycles will feed the strip forward-ly until it projects beyond the endof the slider as shown in Fig. 4.

The slider is then pulled back onto the `barrel firmly into the positionof Fig. 5 and in this position pressure of the inwardly projecting lips25 on the outer surfaces of the jaws I6 and I1 causes the latter tosqueeze the strip i2 very firmly. The brush assembly i3 is inserted intothe breech end of the barrel i6, and the completely assembled eraser isready for use.

With eraser stocks such as previously referred to and having theapproximate dimensions shown in the drawing a length of stock equal toabout twice the thickness of the strip itself is left exposed whenperforming the initial loading operation. The eraser may be used untilthe projecting portion is worn off to a Alength of about le", orsomewhat less than the thickness of the strip, as shown in Fig. 3. Whenit is desired to feed .out additional eraser stoclgwthe slider I'i isfirmly rgrasped as explained before with inwardly deiiecting pressureexerted on the pawls 26 and 21 and moved to the position .shown in Fig.4. A single such stroke will ordinarily feed out enough eraser stock toreplace that worn off and the slider Il may then be returned to thegripping position of Fig. 5. If by any chance a single stroke of theslider does not feed out as much stock as desired, supplementary strokesmay be employed.

As more and more eraser material is successively extended and worn off,the strip I2 is progressively moved forwardly until the tips of thepawls 2S and 2l push against the rearward end of the strip. This is thelimit of "automatic feeding, and at this time the remaining strip oferaser` stock is approximately 1/2 long. As they extended end of thisremaining portion is worn down, some additional material may be extendedby pulling on the exposedv end, so that only a sufficient length ofAmaterial to permit rm grip by the jaws i6 and I1 (approximately 13;")1finally remains as unusable Waste.' It will bey seen that this permitsup to 95% utilization of the eraser material.

f it is desired to change the load from one type of eraser stock toanother, this may be easily done in the following manner: With a normalprojecting length of eraser material extended from the muzzle, theyslider Il is moved back and frth a few times to increase this length andbrought to rest in a position near the forward position. Pressure ofthumb and forefnger is then released, with the result that the pawlsrelease their grip upon the eraser strip. The projecting end of thestrip is then grasped and the entire strip withdrawn from the barrel.The substitute eraser material may then be loaded and fed into positionfor use as previously de- 'f scribed.

in contrast to prior erasers, the eraser design has marked advantages.The slender but rigid metallic barrel gives the typist a firm grip whichpermits manipulation of the short extended portion of eraser stock incontact with the work with precise pressure and accuracy. Bothlongitudinal and transverse erasing operations may be performed withrelative ease and precision. By far the most common typing error is oneof a single letter in a word and since the thickness of the extendedportion (.094") of the eraser is of thesa'me order as the spacing ofpica and elite types, transverse erasure of single characters isaccomplished with accuracy and ease. As the eraser is held in oneparticular position relative to the work for a few strokes and erasermaterial is Worn off, relatively sharp corners are produced on theprojecting piece of stock and with a change in grip on the barrel thesecorners may then be utilized to furnish small areas for further accurateerasing operations. `As these corners, in turn, wear down, others areproduced for further small areal erasure. With a little practice atypist can perform numberless consecutive erasing operations with greataccuracy without any necessity for sharpening the eraser and with fullutilization of the material for constructive erasing. f

When it is necessary to erase at or near the bottom of a typed page,under such conditions that it would be undesirable to move the platen,the eraser of ymy design is very superior. By moving the typewritercarriage to one side or the other, the typist can bring the error intoview, and by taking advantage of the slenderness, length and rigidity ofmy eraser she may erase either longitudinally or transversely. Since theplaten is not rotated, register is intact and erased areas may beimmediately re-typed. The fact of my thatl the'present eraser may beusec'l'vv'vithv great accuracy largely eliminates the need for using anerasing shield, and in turn eliminates the smudging difficultypreviously pointed out. The facts that in the eraser of my design thehands never come into contact with the eraser material and the strip ofmaterial is completely enclosed except for the short projecting sectionmade available for current use result in having very clean andgrease-free material at the point of application to the work, withconsequent elimination of smudging due to foreign matter.-

In addition to the manifest advantages of the eraser of my design foruse on typewritten material, it is very useful for erasure of handWritten or hand drawn pencil or ink lines. When used with certain eraserstocks, previously mentioned, the improved device will erase ink lineswith great accuracy, and when loaded with other material it makes anexcellent tool for draftsmen. Gn the drafting board, as Well as ontypewritten material, an erasing shield may leave marginal smudges;since my eraser may be used with extreme accuracy without a shield, thisdiiiiculty is eliminated. Not infrequently a draftsmany willinadvertently draw a full or solid line where a l broken or dotted lineis called for. With ordinary equipment, the corrective procedure is "tocompletely erase the incorrect line and re-draw it; With the eraser ofmy design, it is only necessary to erase short lengths of line atintervals as desired, thus producing the required interrupted line.Since the instrument can be handled with substantially the rapidity andaccuracy of a pencil, an operation of this sort can often be carried outwith a material saving of time over the ordinary method.

While I have herein shown and described the improved eraser device asembodied in a preferred form of construction, by way of example, it willbe apparent that various modifications might be made in the structurewithout departing from the spirit of the invention. Consequently I donot wish to be limited in this respect but desire to be afforded thefull scope of the appended claims. y y

I claim as my invention:

1. An erasing device, including:L a tubular holder of substantiallyrectangular cross section; an eraser strip of similar cross sectionslidable in said holder; manually operable, one-way feeding meansslidable on saidholder and successively engageable with portions of saidstrip within said holder 'for feeding successive portions of said stripfrom said holder; and flexible means on said holder engageable by saidfeeding means and adapted to be flexed therebyinto engagement with saidstrip for preventing reverse movement of said strip.

2. An erasing device, including: a tubular holder of substantiallyrectangular cross section; an eraser strip of similar cross sectionslidable in said holder; manually operable, one-Way feeding meansreciprocable on said holder and engageable with different portions ofsaid strip during successive reciprocations of said feeding means so asto feed an end of said strip predetermined increments of movement in onedirection from an end of said holder; and resilient means on said holderengageable by said feeding means and adapted to be exed thereby intoengagement with said strip so as to prevent reverse movement of saidstrip.

3. A device as defined in claim 2 in which said feeding means consistsof a slider slidable on said ais/41,4151

holder vand having resilient pawls engageable with opposite sides ofsaid strip to feed the same in'one direction when said :slider is slidin said one direction, said pawls being adapted to slide along saidstrip in the opposite direction when said strip is .held vagainst.movement in said opposite direction by said resilient means, said-pawls overlying said resilient means upon reaching the limit ofmovement of said slider in said opposite direction.

4. A device as dened in claim 3 in which said holder has openingsthrough which said paWls eX- tend to .engage said strip.

5. An erasing device, comprising: a tubular holder of substantiallyrectangular' cross section, said holder having openings in its widersides and resilient tongues projecting inwardly from ysaid sides; aneraser strip of similar cross section slidable in said holder; and aslider reciprocable longitudinally on said holder and having resilientpawls extending through said openings 'and engageable with said strip tofeed the same predetermined increments during successive movements ofsaid slider in one direction so as to project said strip from an end ofsaid holder, said pawls being adapted Vto slide 'relative to .said stripwhen said slider is moved in the opposite direction, said tonguesadapted to engage said .strip to prevent reverse movement thereof`during movement of said slider in said opposite direction, said pawlsoverlying and depressing said .tongues into firm, unyielding engagementwith said strip when said slider reaches the limit of its movement insaid opposite direction .so as to cause said tongues to effectivelyretain said strip in its projected position when the erasing device isapplied to use.

6. An erasing device, comprising: a tubular holder of substantiallyrectangular cross section, said holder having openings in .its widersides and resilient tongues projecting inwardly from said sides; aneraser strip of similar cross Section slidable in said holder; and atubular slider surrounding said holder and reciprocable longitudinallyon said holder and having resilient pawls extending through saidopenings and engageable with said strip to feed the same predeterminedincrements during successive movements of said slider in one directionso as to project said strip from an end of said holder, said pawls beingadapted to slide relative to said strip when said slider is moved in theopposite direction, said tongues being adapted to engage said strip toprevent reverse movement thereof during movement of said slider in saidopposite direction, said pawls overlying and depressing said tonguesinto firm, unyielding yengagement with said strip when said sliderreaches the limit of its movement in said opposite direction so as tocause said tongues to eectively retain said strip in its projectedposition when the erasing device is applied to use.

Iii.

l?. erasing device, comprising: fa tubular beider fof substantiallyrectangular cross section, said holder having openings in its Widersides i:rnd resilient tongues -p'r'oiectin'g inwardly from said sides;fan eraser strip of similar cross section slidable in said holder; atubular slider surrounding said .holder 1land reciprocable.longitudinally on 'said holder and having resilient pawls 4extendingthrough said Aopenings .and engageable with said .strip to feed Athesame predetermined increments dur-ing successive movements of saidslider .in one direction so afs to project said strip 4from an end ofsaid holder, said pawls being .adapted to slide .relative to Ysaid stripwhen said slider is moved in the :opposite direction, 'said tonguesbeing :adapted :to engage said strip to prevent .reverse movementthereof during movement of said slider 2in said opposite direction;Vand. stop means on said holder engageable withsaid slider for limitinglthe extent of reciprocatory movement :of said slider, said pawlsoverlying and depressing said tongues into firm, unyieldin'g `engagementwith said strip :when saidsliderre'achesthe limit of its movement insaid opposite direction so as to cause .said tongues to effectivelyretain said strip in its projected position when .the erasing device isapplied .to use.

8. A .device .as deiined in claim 5 in which said holder is providedwith resilient jaws at its vend from which said vIstr-ip Vis projected,said .jaws ,being 4adapted .to engage opposite sides of said )strip when.iieXed toward each other, said slider being engageable with said jawsto `ilex the same.

9. A device .as denedin claim .5 in which 'said holder isprovided withresilient jaws at its end from which said strip is projected, and saidslider is provided with inturned lips engageable with and adapted todepress .said jaws into firm engagement with said strip when said slideris moved in saidopposite direction.

l0. A device vas defined in claim 5 in which said tongues project insaid one direction within said openings in alignment with said pawls sothat movement of said slider in said opposite direction causes saidpawls to ride up on said tongues to force said tongues .into nrmengagement with 'said strip.

BRUCE BURNS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 173,065 Safford Feb. 1, 1376267,643 Boman Nov. 14, 1882 '799,618 St. John Sept. l2, 1996 1,451,933Weig Apr. 1'7, 1923 1,926,289 Kovacs Sept. 12, 1933

